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A P Dei Tos

Publications and source records attributed to A P Dei Tos.

At least 19 recordsLinked to original sources
PubMed2026

Clinically actionable genomic alterations in breast cancer brain metastases.

BACKGROUND: Breast cancer brain metastases (BCBMs) represent a critical unmet clinical need in metastatic breast cancer (MBC) and the identification of novel therapeutic targets is urgently needed in this context. In this study, we describe clinically actionable targets in BCBMs using comprehensive genomic profiling. PATIENTS AND METHODS: Genomic DNA was extracted from formalin-fixed paraffin-embedded archival BCBM samples and analyzed using the commercially available Agilent SureSelect V6 whole exome sequencing (WES) kit and an Illumina NovaSeq 6000 platform. Pathogenic alterations were classified as actionable alterations (AAs) if they met the updated MBC or tumor-agnostic ESMO Scale for Clinical Actionability of Molecular Targets (ESCAT) I or II criteria of the ESCAT scale. RESULTS: WES data from 56 BCBM samples were available [33.9% hormone receptor (HR)-negative/human epidermal growth factor receptor (HER)2-negative; 25.0% HR-positive/HER2-negative; and 38% HER2-positive]. ESCAT I/II AAs were detected in 76.8% (n = 43) of all BCBMs and the most frequently detected AAs were in genes involved in the homologous recombination repair pathway (BRCA1/BRCA2/PALB2; 53.6% overall). Biallelic inactivation of BRCA1, BRCA2, or PALB2 was observed in 19.6% of samples, with higher rates in HER2-negative BCBMs (26% in HR-negative /HER2-negative and 21% in HR-positive/HER2-negative). ESCAT I/II PIK3CA/AKT1/PTEN pathway alterations were present in 48.2% of samples and, in particular, in 50% of HR-positive/HER2-negative BCBMs. No ESR1 mutation was detected in HR-positive/HER2-negative BCBMs. The prognostic impact of previously described AAs was evaluated overall and according to breast cancer subtype. Twenty-three BCBMs (41%) were classified as HER2-positive; among these, 3 (13%) presented a hotspot PIK3CA mutation and 7 (30%) presented a PTEN deletion. Among patients with HER2-positive BCBMs, the identification of a hotspot PIK3CA mutation was significantly associated with worse prognosis. CONCLUSIONS: ESCAT I/II actionable genomic alterations are frequent in BCBMs, highlighting the potential for genomically targeted treatments in this setting.

ESCAT↗
PubMed2006

Gastrointestinal stromal tumours overexpress fatty acid synthase.

Fatty acid synthase (FASN), a key enzyme for de novo lipogenesis, is overexpressed in many malignant tumours and is associated with aggressive biological behaviour. FASN expression and its possible relationship with more aggressive behaviour in gastrointestinal stromal tumours (GISTs) have not been addressed to date. Here, FASN expression was assessed by immunohistochemistry in 60 primary GISTs (28 low/intermediate risk and 32 high risk) and seven metastatic GISTs. Sixteen smooth muscle gastrointestinal tumours were used as controls. FASN was overexpressed in 36 of 60 GISTs (60%): in 12 of 28 (42%) low/intermediate-risk GISTs and in 24 of 32 (75%) high-risk GISTs (p<0.05). Two primary and seven metastatic GISTs and five GIST cell lines (GIST882, GIST430, GIST522, GIST62, and GIST48), analysed by western blot, showed variable FASN expression. Most metastatic samples expressed high levels of FASN protein. Additionally, seven of 60 GISTs showed a proliferation rate higher than 10% by Ki67 and all of them expressed FASN (p<0.04). Finally, proliferation and apoptosis were investigated after FASN silencing in GIST882 cells, which displayed the highest FASN expression. siRNA-mediated FASN knock-down inhibited expression of the proliferation marker cyclin A, whereas no changes in p27 and cleaved PARP expression were seen. It is concluded that FASN is preferentially overexpressed in high-risk and metastatic GISTs, and that its overexpression likely contributes to cell proliferation.

Biomarkers, Tumor↗
PubMed2006

Jaw1/LRMP, a germinal centre-associated marker for the immunohistological study of B-cell lymphomas.

Jaw1, also known as lymphoid-restricted membrane protein (LRMP), is an endoplasmic reticulum-associated protein. High levels of Jaw1/LRMP mRNA have been found in germinal centre B-cells and in diffuse large B-cell lymphomas of 'germinal centre' subtype. This paper documents Jaw1/LRMP expression at the protein level in human tissues by immunohistochemical and western blotting analysis using an antibody reactive with paraffin-embedded tissues. Jaw1/LRMP was highly expressed in germinal centre B-cells (in keeping with gene expression data), in 'monocytoid B-cells', and in splenic marginal zone B-cells. It was absent, or present at only low levels, in mature T-cells, although cortical thymocytes were weakly positive. Among lymphoid neoplasms, Jaw1/LRMP was found in germinal centre-derived lymphomas (follicle centre lymphoma, Burkitt's lymphoma, lymphocyte-predominant Hodgkin's disease) but not in T-cell neoplasms (with the exception of a single T lymphoblastic lymphoma). Classical Hodgkin's disease and myeloma lacked Jaw1/LRMP but many cases of chronic lymphocytic leukaemia (but not mantle zone lymphoma) were Jaw1/LRMP-positive. Approximately half of the marginal zone lymphomas were Jaw1/LRMP-positive. In diffuse large B-cell lymphomas, Jaw1/LRMP was found in three-quarters (24/32) of the cases classified phenotypically as being of 'germinal centre' type, but it was also expressed in almost half (13/28) of the 'non-germinal centre' cases. A similar proportion of 'non-germinal centre' cases were positive for the protein products of two other genes expressed highly in germinal centre cells (HGAL/GCET2 and PAG). The fact that all three of these proteins are expressed in a significant proportion of diffuse large B-cell lymphomas assigned to the 'non-germinal centre' category indicates that the immunophenotypic categorization of diffuse large B-cell lymphoma according to cellular origin may be more complicated than currently understood. Finally, the expression of Jaw1/LRMP in other types of lymphoma and in non-lymphoid tissues/tumours may be of interest in differential diagnosis and research.

Adrenal Glands↗
PubMed2006

Classification of pleomorphic sarcomas: where are we now?

Until a decade ago, so-called pleomorphic and storiform malignant fibrous histiocytoma (MFH) represented the most frequently diagnosed sarcoma, accounting for approximately 40% of adult mesenchymal malignancies. However, the latest World Health Organization classification of soft tissue tumours considers MFH a synonym for undifferentiated pleomorphic sarcoma. Historically, the term MFH was introduced in the medical literature in 1963 by Ozzello, O'Brien and Stout, on the basis of the acquisition of phagocytic properties observed in cultured fibroblasts. The existence of MFH as a well-defined clinicopathological entity became rapidly very popular and by the mid 1980s MFH represented the most common sarcoma in adults. With the advent of electron microscopy, immunohistochemistry and molecular genetics, it became clear that the so-called "facultative fibroblast" theory had no scientific grounds and, in 1992, a milestone paper eventually brought attention to the concept that MFH merely represented a morphological pattern shared by a wide variety of poorly differentiated malignant neoplasms, which include specific subtypes of pleomorphic sarcomas. Currently, accurate subclassification of pleomorphic sarcomas is mandatory as it enables recognition of non-sarcomatous lesions as well as pleomorphic neoplasms not associated with aggressive behaviour. Furthermore, as myogenic differentiation predicts aggressive clinical behaviour among pleomorphic sarcomas, precise histotyping allows prognostic stratification of patients.

Humans↗
PubMed2005

Assessing epidermal growth factor receptor expression in tumours: what is the value of current test methods?

Over-expression of the epidermal growth factor receptor (EGFR) in tumours is associated with aggressive disease and poor clinical prognosis. In theory, the EGFR status of a tumour provides an indication of the likelihood of response to EGFR-targeted therapy. However, the clinical data do not support a relationship between EGFR expression and response to EGFR-targeted therapies cetuximab, gefitinib and erlotinib. Recently, patients who appear to lack EGFR expression have been shown to respond to cetuximab. Possible causes for this paradox include false negative results due to a lack of sensitivity in the detection system, heterogeneity of EGFR expression within the tumour and specific mutations that mediate response to the tyrosine kinase inhibitors. Immunohistochemistry is the most reliable assay for EGFR expression but its interpretation is confounded by the lack of non-standard techniques. Other approaches for measuring EGFR expression can be considered at best exploratory at this point. Further work is needed to identify how EGFR contributes to carcinogenic and metastatic processes. As tumours that appear to be EGFR negative can respond to cetuximab, there is some doubt as to the usefulness of immunohistochemistry as a screen to select patients for treatment. Histopathology will continue to be essential for unravelling the role of this enigmatic molecule and refining its status as a legitimate target in cancer therapy.

Enzyme-Linked Immunosorbent Assay↗
PubMed2005

Consensus meeting for the management of gastrointestinal stromal tumors. Report of the GIST Consensus Conference of 20-21 March 2004, under the auspices of ESMO.

BACKGROUND: The management of gastrointestinal stromal tumors (GIST) has evolved very rapidly in the last 4 years. The objectives of this international consensus meeting were to describe the optimal management procedures for patients with GIST in localized and advanced stages, as well as research issues for the future. MATERIALS AND METHODS: A panel of experts from six specialties, including pathology, molecular biology, imaging, surgery, medical oncology and methodologists for clinical practice guidelines from different European and extra European sarcoma societies were invited to a 2-day workshop. Several questions were selected by the organizing committee prior to the conference. Selected panelists reviewed the current levels of evidence for each point, and presented their conclusions during the meeting. These proposals were discussed, and consensus points were identified and categorized according to the Standard Options Recommandations (SOR) of the French Federation of Cancer Centers and National Comprehensive Cancer Network (NCCN). RESULTS: Thirty-two consensus points were identified, most from categories 2A of the NCCN and B2 of the SOR. Among these, the standard histological examination with immunohistochemical analysis using CD117, CD34, PS100, desmin and smooth muscle actin is considered standard. Molecular biology for the identification of KIT and PDGFRA mutation is an optional diagnostic procedure for GIST with negative CD117 staining, and otherwise is considered a research procedure. Complete tumor resection with negative tumor margins is the standard surgical treatment. Adjuvant imatinib after optimal tumor resection as well as neo-adjuvant imatinib remain experimental approaches to be performed within prospective clinical studies. Imatinib should be started at the date of diagnosis of metastatic relapse and given until development of intolerance or progressive disease. The optimal criteria for tumor response to imatinib remain to be delineated, and should include not only tumor size reduction or disease stabilization, but also reduction of tumor density (Hounsfield Units) on computed tomography and metabolic activity (i.e. reduction of FDG uptake on positron emission tomography). In a substantial proportion of patients, stable disease and even increase in tumor size may be associated with pathologic response to imatinib therapy, and available survival data indicate that the survival of these patients is similar to that of patients with conventional tumor response. Metastasis resection is an experimental procedure. CONCLUSIONS: Consensus points in clinical management of GIST as well as questions for future clinical trials were identified during this consensus conference on GIST management.

Benzamides↗
PubMed2005

Characterization of thyroid 'follicular neoplasms' in fine-needle aspiration cytological specimens using a panel of immunohistochemical markers: a proposal for clinical application.

The distinction of benign from malignant follicular thyroid neoplasms remains a difficult task in diagnostic fine-needle aspiration cytology, and some discrepant results have been reported for the individual immunocytochemical markers of malignancy proposed so far. The aim of this study was to test if the combined use of a panel of markers could improve the diagnostic accuracy in the preoperative cytological evaluation of 'follicular neoplasms' in an attempt to reduce the number of thyroidectomies performed for benign lesions. The immunocytochemical expression of galectin-3, HBME-1, thyroperoxidase, cytokeratin-19 and keratan-sulfate was retrospectively analyzed in 125 consecutive fine-needle aspiration samples (cell blocks) of indeterminate diagnoses of 'follicular thyroid neoplasm', and compared with their corresponding surgical specimens, including 33 follicular carcinomas, 42 papillary carcinomas and 50 follicular adenomas. Statistical analysis on each marker confirmed that galectin-3 and HBME-1 were the most sensitive (92% and 80% respectively) and specific (94% and 96% respectively) molecules. The use of these two markers sequentially in non-oncocytic lesions (testing HBME-1 as a second marker whenever galectin-3 proved negative) increased the sensitivity and specificity up to 97% and 95% respectively. In oncocytic lesions, HBME-1 proved to be less sensitive, and the sequential combination of galectin-3 and cytokeratin-19 reached 100% of both specificity and sensitivity. Our data showed that, as compared with the use of single markers, the sequential combination of two markers represents the most accurate immunohistochemical panel in managing patients with a fine-needle aspiration biopsy diagnosis of 'follicular neoplasms', especially in otherwise controversial categories such as oncocytic tumours. The combination of three or more markers did not substantially improve the diagnostic accuracy of the test.

Adenocarcinoma, Follicular↗
PubMed2001

Analysis of p53 mutation and expression in pleomorphic xanthoastrocytoma.

Pleomorphic xanthoastrocytoma (PXA) is a rare, superficially situated tumor that most frequently occurs in the temporal lobe of young adults and is often associated with seizures. It generally has a relatively favorable prognosis. Prior studies have shown that TP53 mutations may occur in up to 25% of PXAs, suggesting that PXA may have an etiology similar to diffuse astrocytoma rather than pilocytic astrocytoma. In the present study, we performed immunostaining for p53 protein and examined the mutation status of exons 5-8 of the p53 gene in 55 PXAs, 8 of which had undergone one or multiple recurrences. Of 55 primary PXAs, 35 (64%) showed staining in <1% of tumor cells, 15 (27%) in 1-10%, 4 (7%) in 11-50%, and only 1 (2%) in >50%. No significant increase in p53 protein expression was noted in recurrences, even when associated with increased histological anaplasia. We found a TP53 heterozygous mutation in exon 7 in 1 of 47 primary tumors that yielded useable DNA, and in its recurrence 3 years later. This tumor, a grade II PXA, did not show signs of anaplastic transformation at recurrence. Eleven additional recurrences from 7 patients, 5 of which showed signs of histological anaplasia, did not show TP53 mutations in exons 5-8. Based on our data, the p53 mutation appears to be an uncommon (2%) genetic event in PXA formation and does not appear to be involved in tumor progression. Consequently, our findings suggest that the genetic events that underlie PXA formation differ from those involved in diffuse astrocytoma.

Astrocytoma↗
PubMed2001

Morphological analysis of nevoid melanoma: a study of 20 cases with a review of the literature.

Nevoid melanoma is a rare variant of melanoma characterized by deceptive morphologic features reminiscent of a benign melanocytic nevus. Twenty (13 nodular, 7 verrucous) nevoid melanomas were reviewed with the goal of identifying the predominant architectural patterns, cytologic features, and prognostic indicators. Although at scanning magnification, many lesions showed a strong resemblance to banal compound or dermal nevi, careful inspection in all cases demonstrated subtle pleomorphism and impaired maturation with depth, invariably accompanied by multiple dermal mitoses. Four tumors recurred and three metastasized, with subsequent death of the patients. Follow-up information for a period of at least 3 years was available in eight cases. In this group, mortality was 37.5%, the metastasis rate was 37.5%, and the local recurrence rate was 75%, with an average tumor thickness of 2.5 mm. We conclude that nevoid melanoma may be distinguished from a benign melanocytic nevus by a high index of suspicion, a careful analysis of architecture, and attention to cytologic features. Our data and a review of the literature do not support the notion that nevoid melanoma has a better prognosis than ordinary melanoma.

Adult↗
PubMed2001

[Measurement of HER-2/neu in breast cancer: which methodologic approach?].

HER-2/neu (c-erbB2) is overexpressed or amplified in 15%-35% of breast cancers. HER-2 testing has become of paramount importance as it represents a key therapeutic, prognostic and predictive parameter. HER-2 is associated with ER/PgR negativity, high histologic grade, high proliferative index, and increased number of metastatic lymph nodes. In N+ patients, HER-2 represents a negative prognostic factor. HER-2 also represents a predictive factor. In fact, HER-2+ patients appear to be resistant to the CMF regimen and comparatively more sensitive to anthracyclins such as Herceptin. HER-2 testing is currently performed utilizing two main methods: gene amplification is usually determined by fluorescence in situ hybridization (FISH), whereas protein overexpression is determined by immunohistochemistry (IHC). The comparison between FISH and IHC assays demonstrates a considerably high degree of concordance (around 90%). When dealing with cases scored as 3+ (according to the FDA licensed scoring method), such a concordance approaches 100%. In consideration of greater technical simplicity as well as of cost-effectiveness, IHC represents the ideal screening method for HER-2 testing. FISH analysis remains valid for HER-2 evaluation in those cases in which IHC fails to provide unequivocal data.

Breast Neoplasms↗
PubMed2001

Well-differentiated liposarcoma (atypical lipomatous tumors).

Well-differentiated (WD) liposarcoma accounts for about 40% to 45% of all liposarcomas therefore representing the larger subgroup of adipocytic malignancies. It tends to occur equally in the retroperitoneum or the limbs followed by the paratesticular area and the mediastinum, with a peak incidence between the fifth and the seventh decades. WD liposarcoma is further subdivided in the adipocytic (lipoma-like), sclerosing, inflammatory, and spindle cell subtypes, of which the first two are by far the commoner. WD adipocytic liposarcoma is composed of a relatively mature adipocytic proliferation, featuring cell size variation as well as at least focal nuclear atypia. A varying number (from many to none) of lipoblasts may be found. Sclerosing WD liposarcoma is characterized microscopically by the presence of scattered distinctive bizarre stromal cells and multivacuolated lipoblasts set in a fibrillary collagenous background. Inflammatory liposarcoma represents a rare variant of WD liposarcoma in which a chronic inflammatory infiltrate predominates to the extent that the differential diagnosis is mainly with nonadipocytic lesions such as inflammatory myofibroblastic tumor, Castleman's disease, and Hodgkin's as well as non-Hodgkin's lymphomas. Spindle cell liposarcoma is the rarest variant and is composed neural-like spindle cell proliferation set in a fibrous and/or myxoid background and associated with an atypical lipomatous component which usually includes lipoblasts. Cytogenetically, WD liposarcoma appears to be relatively homogenous exhibiting characteristic ring as well as giant marker chromosomes containing amplified genetic material derived from the 12q13-15 chromosome region. As WD liposarcomas of any type have no potential for metastasis unless they undergo dedifferentiation, the opportunity to replace the term "WD liposarcoma" with a less frightening denomination has produced a long, sharp debate. WD liposarcoma and atypical lipoma should be considered as synonyms and their use should therefore be determined by the degree of reciprocal comprehension between the surgeon and the pathologist to prevent either inadequate or excessive treatment.

Adipocytes↗
PubMed2001

Myxoid and round cell liposarcoma: a spectrum of myxoid adipocytic neoplasia.

Myxoid and round cell liposarcoma accounts for about 30% to 35% of all liposarcomas and, even if still classified by the World Health Organization (WHO) as 2 distinct subtypes, share both clinical and morphologic features. Lesions combining both patterns are frequent and wide agreement exists in considering round cell liposarcoma as the high grade counterpart of myxoid liposarcoma. Furthermore, myxoid and round cell liposarcoma share the same characteristic chromosome change represented most frequently by a reciprocal translocation t(12;16)(q13;p11) that fuses the CHOP gene with the TLS gene. Clinically, myxoid and round cell liposarcoma tend to occur in the limbs with a peak incidence ranging between the third and the fifth decade and exhibit overall a metastatic rate of approximately 30%. A peculiar tendency to metastasize to the soft tissue is observed that should not be interpreted as multicentricity. Microscopically, purely myxoid liposarcoma is composed by a hypocellular spindle cell proliferation set in a myxoid background and associated with a varying number of monovacuolated lipoblasts. The most helpful morphologic clue is represented by the presence of a thin-walled capillary network organized in a plexiform pattern. The most important morphologic variation observed in myxoid liposarcoma is represented by the occurrence of hypercellular areas that may exhibits an undifferentiated round cell morphology. On the basis of the percentage of hypercellularity/round cell formation, a myxoid/round cell liposarcoma (more than 25% hypercellular/round cell areas) and a round cell liposarcoma (more than 75% hypercellular/round cell areas) are somewhat arbitrarily recognized. Both the recognition and the quantification of hypercellular/round cell areas represents a crucial step in the evaluation of this liposarcoma subtype because hypercellularity appears to correlate with the clinical outcome. In consideration of the intrinsic difficulty in establishing accurately the percentage of high grade areas as well as of application of different cut off values, it appears safer to consider any amount of hypercellularity as prognostically relevant. Careful as well as extensive sampling is mandatory to permit detection of the smallest amount of hypercellularity. The differential diagnosis of myxoid liposarcoma includes benign lesions, such as myxoid spindle cell lipoma, intramuscular myxoma and lipoblastoma, and malignant ones such as low grade myxofibrosarcoma, and extraskeletal myxoid chondrosarcoma. In consideration of the great morphologic variability, the application of both immunohistochemistry and genetics has proved helpful in sorting out the more challenging cases.

Adipocytes↗
PubMed2000

Coordinated expression and amplification of the MDM2, CDK4, and HMGI-C genes in atypical lipomatous tumours.

Atypical lipomatous tumours (ALTs) represent a distinctive subset of mesenchymal neoplasms featuring mature adipocytic differentiation. Most ALTs are characterized cytogenetically by the presence of supernumerary ring and/or long marker chromosomes derived from the chromosomal region 12q13-15. The 12q13-15 chromosome region contains several genes which may play an important role in human tumorigenesis. A series of ALTs was analysed by investigating the MDM2, CDK4, and HMGI-C genes and their proteins. The study was extended to a series of ordinary lipomas, to determine whether the immunohistochemical investigation of these gene products might play any diagnostic role. Cytogenetic analysis revealed the presence of various cytogenetic aberrations involving the 12q13-15 region in 11/18 (61%) lipomas and of ring chromosomes in all ALTs. Overexpression of mdm2 protein was observed in 6/12 (50%) atypical lipomatous tumours. All lipomas were mdm2-negative. cdk4 overexpression was present in 100% of ALTs. Weak cdk4 immunopositivity was detected in 2/18 (11%) ordinary lipomas in a minority of cells. HMGI-C immunopositivity was observed in 10/12 (83%) ALTs. Positive immunoreactivity was also observed in 8/18 (44%) lipomas. Southern blot analysis revealed amplification of the CDK4 and MDM2 genes in 3/5 ALTs analysed. HMGI-C was amplified in 3/5 cases and was deleted in one case. Mutation analysis of the CDK4 gene did not demonstrate any mutation. These data support the hypothesis that ordinary lipomas may form a molecular genetic and morphological continuum with ALT. At one end of the spectrum are lipomas characterized by 12q13-15 rearrangements and HMGI-C activation and at the other end are ALTs with ring chromosomes, 12q13-15 amplification with overrepresentation of the HMGI-C, CDK4 or MDM2 genes, and aberrant cdk4, mdm2, and HMGI-C protein expression. These findings not only provide insights into the molecular pathogenesis of lipomatous tumours, but also indicate that the immunohistochemical analysis of mdm2 and cdk4 may help to increase diagnostic accuracy.

Adult↗
PubMed2000

Liposarcoma: new entities and evolving concepts.

Liposarcoma is the most common soft tissue sarcoma and accounts for approximately 20% of all mesenchymal malignancies. In the last decade, the results of several studies have led to the delineation of new variants as well as to the introduction of new concepts, mainly as a result of the fruitful interactions between genetics and pathology. Spindle cell liposarcoma represents an uncommon variant of well-differentiated liposarcoma. It tends to occur in adults and often involves the subcutaneous soft tissue. However, from the observation of a larger number of cases, the anatomic distribution of spindle cell liposarcoma seems to be comparable to that of the other well-differentiated liposarcoma subtypes. Spindle cell liposarcoma tends to recur locally and may dedifferentiate. Morphologically it is composed of a fairly bland neural-like spindle cell proliferation set in a fibrous and/or myxoid background and is associated with an atypical lipomatous component. Great debate has been generated by the introduction of the term atypical lipoma to emphasize the fact that well-differentiated liposarcoma shows risk of local recurrence but no potential for metastasis. In our opinion well-differentiated liposarcoma and atypical lipoma should be considered synonyms that describe lesions identical both morphologically and kayotypically. Dedifferentiated liposarcoma is a distinct type of liposarcoma in which transition from low-grade to high-grade nonlipogenic morphology within a well-differentiated liposarcoma is observed. The transition usually occurs in an abrupt fashion; however, in rare cases it can be more gradual. Recently, it also has been proposed that dedifferentiated liposarcoma should be further classified into low and high grade. Dedifferentiated liposarcoma rarely exhibits heterologous (most often myoid) differentiation. A peculiar "neural-like whorling pattern" of dedifferentiation also has been described recently. Surprisingly, the clinical outcome of dedifferentiated liposarcoma is less aggressive that in other high-grade pleomorphic sarcomas but genetic as well as molecular data exist that may partiallyjustify such a discrepancy. Myxoid and round cell liposarcoma, even if still classified by the World Health Organization as two distinct subtypes, share both clinical and morphologic features. Lesions combining both patterns are very frequent and wide agreement exists in considering round cell liposarcoma as the high-grade counterpart of myxoid liposarcoma. Furthermore, myxoid and round cell liposarcoma share the same characteristic chromosome change. Albeit rare, it has been recently shown that liposarcoma indeed can occur as a primary skin lesion. It often presents clinically as a dome-shaped or polypoid lesion that, histologically, most frequently shows high-grade morphologic features but carries a comparatively good prognosis. Considering currently available data, the most logical classification of liposarcoma is into three main groups: (1) well-differentiated liposarcoma (including adipocytic, sclerosing, inflammatory, spindle-cell, and dedifferentiated variants), characterized by ring or long markers chromosomes derived from the long arm of chromosome 12; (2) myxoid and round cell (poorly differentiated myxoid) liposarcoma, characterized in most cases by a reciprocal translocation t(12;16)(q13;p11); and (3) pleomorphic liposarcoma, characterized by complex karyotypes.

Adult↗